The present invention relates to a switch and circuit breaker construction such as one which is typically utilized for optionally reversing the direction of current flow to a motor of an electric hand tool such as a power screwdriver, an electric drill, or an electric saw, and more particularly relates to such a switch and circuit breaker construction which can be compactly accomodated.
In the prior art, in such a particular case when a switch is provided for optionally reversing the direction of current flow to a motor of an electric hand tool such as a power screwdriver, an electric drill, or an electric saw, and when also a circuit breaker is provided to said electric hand tool for ensuring that the supply of electricity is interrupted when the amperage of electricity supply increases above a determinate level, it has been practiced to supply said switch and said circuit breaker as a pair. However, since in such an arrangement said switch and said circuit breaker are arranged separately in the electric hand tool, the internal space within the body of said electric hand tool is not utilized with very great efficiency, thus causing a waste of space. This makes the job of assembling the electric hand tool more difficult and causes an increase in the requirement for the size of said electric hand tool. Further, there is a concomitant difficulty with the assembly difficulty for said electric hand tool, due to the fact that said switch and said circuit breaker exist as two separate units. And the problem of parts management is also considerable, as is the storage requirement for such parts.
Also, as a subsidiary desideratum, a typical such switch as conventionally provided for optionally reversing the direction of current flow to a motor of an electric hand tool such as a power screwdriver, an electric drill, or an electric saw is a rotary type switch. However, such a rotary type switch tends to be rather complicated, incorporating a relatively large number of component parts, and accordingly a limit upon the compactness of the design of the switch is imposed. Therefore, the efficiency with which such a switch can be accomodated in the body of the electric hand tool is relatively poor. Further, the operation of such a reversing switch is relatively cumbersome for the user, because a rotary motion is required.
In the case of a slide switch such as might be conceived of for use as such a switch for optionally reversing the direction of current flow to a motor of an electric hand tool such as a power screwdriver, an electric drill, or an electric saw, typically such a slide switch is provided with terminals which are insert molded into a switch base, and with a slider member which slides one or more movable contact members over said terminals for switching over said terminals by connecting together various combinations thereof. However, since such a movable contact member or members is or are typically fixedly supported by the slider member, the problem tends to arise that the contact surface of such a movable contact member tends to become non uniform, and the contact thereof against the terminals over which it slides tends to become unstable, thereby possibly engendering poor contact and low reliability of the switch as a whole.